Online PHP editor | output for YkK5j

<?php namespace GeneratorExample; class Pipeline { protected $generators = []; function __construct() { foreach (func_get_args() as $g) { $this->add($g); } } function add(callable $generator) { $this->generators[] = $generator; return $this; } function __invoke() { $inputs = func_get_args(); foreach ($this->generators as $g) { $generator = call_user_func_array($g, $inputs); $inputs = [$generator]; } return $generator; } } $uppercase = function(\Traversable $in) { foreach ($in as $word) { yield strtoupper($word); } } $reverse = function(\Traversable $in) { foreach ($in as $word) { yield strrev($word); } } $println = function(\Traversable $in) { foreach ($in as $line) { echo "$line\n"; } } $words = new \ArrayIterator(["foo", "bar", "baz"]); $p = new Pipeline($uppercase, $reverse, $println); $p($words);